Plugboard system

ABSTRACT

A plugboard system comprising opposed contact board means, one of which has receiver means for receiving and securing the other board means, moving it toward and then along the plane of the one board means for contact engagement. The board means are of apertured insulation, metal-coated to form shielding and grounding. One board means has a shielding grid which isolates the mated contact ends from each other and engages the coatings. Patchcord connectors form the contacts on one board means, and insulation-sleeve-mounted spring elements form the contacts in the other board means.

United States Patent 11 1 Feese r et al.

1451 Dec. 25, 1973 [54] PLUGBOARD SYSTEM 2,903,670 9/1959 Sity 339/128 2,919,421 12/1959 Modrey... 339/177 E X [75] lm'emorswlham 3,337,833 8/1967 Creedon 339 221 M x Cumberland; Cornelius Wllllam 3,296,363 1 1967 Landig et al. 339 177 R x Boslan H h y; J p LaRue 3,074,045 1 1963 Overholser 339 177 R Lockard, Harrisburg; Dale Brice Mummey Camp H111 an of Primary Examiner-Richard E. Moore [73] Assignee: AMP Domestic lnc., Harrisburg, Pa. Attorney-William g, Ronald rald K. Kita, Frederick W. Raring, Jay L. Seitchik, [22] Flled' 7 May 1971 John R. Flanagan and Allan B. Osborne [21] Appl. No.:'140,411

Related US. Application Data [5 7] ABSTRACT [60] Continuation of Ser. No. 760,379, July 29, 1968, A plugboard System comprising opposed Contact g zg g 5 98914 board means, one of which has receiver means for rea ceiving and securing the other board means, moving it [52] Us Cl 339/9l P 339/177 E 339/2l7 J toward and then along the plane of the one board [51] H01r 11/18 i 13/54 means for contact engagement. The board means are 58] Fie'ld 339/177 217 J 91 of apertured insulation, metal-coated to form shielding 339/183 and grounding. One board means has a shielding grid which isolates the mated contact ends from each other [56] References Cited and engages the coatlngs. Patchcord connectors form the contacts on one board means, and 1nsulat1on- UNITED STATES PATENTS sleeve-mounted spring elements form the contacts in 3,235,834 2/1966 O'Keefe et al. 1, 339/177 R the other board means, 2,983,895 5/1961 Pasik..... 3,206,540 9/1965 Cohen 339/ 177 R X 12 Claims, 14 Drawing Figures PLUGBOARD SYSTEM CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of Application Ser. No. 760,379, filed July 29, 1968, which is in turn a division of Application Ser. No. 598,014, filed Nov. 30, 1966, now U. S. Pat. No. 3,430,183.

BACKGROUND OF THE INVENTION This invention relates to a plugboard system of the type utilized to program electrical connections for performing circuit functions in computers and like equipment.

In U. S. Pat. No. 2,939,100 to W. S. Watts, granted May 31, 1960, there is disclosed a plugboard for patchcord systems having an improved shielded contact board construction. The type of system disclosed in the Watts patent has a particular use in applications wherein the electrical signals connected by the system are of relatively low signal level and, therefore, subject to degradation from stray radio frequency interference called RFl or from degradation caused by cross-talk between signal paths which are physically close together in the system. The Watts type system provides a shielding between contact paths as mounted in the plugboard, but does not provide a shielding which is continuous through the system.

SUMMARY OF THE INVENTION shielded patchcord which includes a latching structure capable of repeated use in a plugboard without excessive wear on such board.

It is another object of the invention to provide a plugboard construction utilizing plastic and plating materials for components which may be made without extensive machining and at the same time which offer an improved shielding of signal paths and an improved grounding of shield paths relative to signal conductive paths in the system.

It is still a further object of the invention to provide an improved receiver and drive mechanism for a plug- .board system.

The foregoing objectives are attained by the present invention through a plugboard construction which features as a board structure molded plastic front and rear board members overplated with conductive material. The board members serve as the principal means for mounting and positioning contact spring members and patchcord plug members for a controlled interconnecswitching function. Shielding is extended between the boards and made to surround each individual contact spring and patchcord path in the zone of engagement between spring and patchcord. The rear board contact springs are individually mounted in an insulating insert in plated apertures within the rear board so as to be surrounded by conductive and shielding material from the point of entry in the board, through the board and out of the board. The patchcords of the system include a metal and plastic structure which surrounds the center conductor of shielded patchcord cable and extends a shielding and conductive covering from the point of connection with the shielding of the cable forwardly toward the end of the patchcord. A plastic detent structure is provided on the patchcord to latch the patchcord in a plated aperture in the front board. This plastic detent structure is shaped to provide a latching function with minimum wear to the plating of the front board. Beneath the plastic detent structure is a further plastic member plated over to surround the signal path formed by the center contact of the patchcord. The patchcord center contact is made to extend slightly forward of the shield structure. This portion is positioned so that in use it is surrounded by the shield which extends forward of the front face of the rear board. In this manner all contact paths are individually shielded when the system is in use. The system includes a receiver structure which permits a front board to be manually placed in a proper position for operation by insertion upon four hooks disposed at the sides of the rear board. These hooks are made to slide inwardly under a manual force to carry the front board into engaging position relative to the back board. The hooks are provided with a relief to permit a camming mechanism to engage the front board and drive it upwardly in a parallel motion to effect a contact engagement between patchcords and rear board contact springs and thereby a switching operation.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective showing the plugboard system of the invention with the front board thereof displaced from the rear board thereof;

FIGS. 2, 3, 4 and 5 are schematic views from the side showing the front and rear boards prior to insertion, following insertion and following closure of the receiver mechanism to effect switch operation;

FIG. 6 is an elevation and partial section showing the rear board camming mechanism;

FIGS. 7, 8, 9 and 10 are side elevations showing the board receiver mechanism in various positions prior to insertion, following insertion and following the camming operation of the closure mechanism; I

FIG. 11 is a sectional view showing a portion of a front board and a rear board having contact elements therein and positioned prior to insertion;

FIG. 12 is a section showing part of the rear board and front board having contact elements therein following insertion of the front board;

FIG. 13 is a section drawn through lines l313 in FIG. 12; and

FIG. 14 is a longitudinal section, considerably envention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a plugboard system which includes a front board 12 in a position just prior to insertion into a receiver mechanism of a back board 32. The front board is comprised of an outer frame 14 of a metallic construction which surrounds and supports a plurality of boards shown as 16, each including a plurality of apertures such as 18, across the surface thereof. The apertures 18 receive patchcords such as 120 shown in FIG. 11, which are individually connected in pairs by a coaxial and shielded electrical lead 122. Frame 14 includes side pieces 17 and top, center and bottom pieces 27 as shown. The side pieces each have secured therein at the top and at the bottom, pin members such as 28 and 30. These pin members are made to extend outward of the frame and are positioned thereon to mate with hook members in the back board receiver.

The patchcords 120 are plugged in various patterns into the various apertures 18 of the front board to define a given program of interconnections to be made when the front board is inserted in the receiver and closure is effected. Handles 26 are provided on each side of the front board 12 to facilitate manual handling of the board.

The back board 32 includes an outer metallic frame 32' which surrounds and supports a plurality of back board members such as 36, the details of which will be described hereinafter. A receiver and closure mechanism is mounted on the back board, including slidable hook members shown as 88 in FIG. 1, which fit into a frame side member such as 34. Within the bottom frame member shown as 35 in FIG. 1 is a camming mechanism which operates to drive the front board as positioned within the rear board receiver to effect closure between patchcords and contact springs carried in the rear board. The camming mechanism is driven by a shaft shown as 54 connected to cams, described in detail hereinafter, under a force developed by an operating arm 52.

FIGS. 2-5 show in general the structure which accomplishes switch operation. In FIG. 2 the front board 12 is shown positioned out from and just prior to insertion in the receiver mechanism of the rear board. The operating handle 52 is in theopen position so that the cam 66 driven thereby is in the down position. The hook members 88 of the receiver mechanism are in the out position, ready to receive the pin members 28 and on each side of the front board frame. FIG. 3 shows the front board 12 positioned in the receiver mechanism with the pin members 28 and 30 seated within grooves such as 102 in hook members 88 and held therein against accidental displacement by a projecting portion 104 forward of the recesses 102 in the members 88. At this time the operating handle is still in the open position and cam 6.6 is still in the down position. A manual force to the left relative to FIG. 3 upon the handles 26 on the front board operates to push against the hook members which are displaced to the left, permitting the front board to move within the receiver mechanism so that the patchcords 120 are positioned parallel to but slightly before the contact springs 110 of the rear board. The system as shown in FIG. 4 is now ready for closure of handle 52 to operate the cam and drive the board 12 upwardly to effect closure between the patchcords 120 andthe contact springs 11.0. This closure is shown in FIG. 5. Operation of the system to the position of FIG. 5 effects a selected connection of pairs of leads. Each pair includes a path from a lead shown as 111, connected to a contact spring 110, through an individual patchcord 120 and through an individual shielded lead 122 to a connected patchcord 120, a connected contact spring 110 and a further lead 111. In accordance with the invention the path which extends through the system as described is shielded completely from a point of entry at the back of the rear board through the contact paths and patchcord leads and out of the back of the back board.

The operating handle for the system thus far shown is made to be utilized when a system is mounted adjacent to a flat surface such as at the rear portion of a working table or cabinet top. This type of position is frequently necessary in an analogue computer application wherein the operator, seated at the console of the computer, has need for access to the plugboard system for operation and has need for a flat surface adjacent thereto for other purposes. The operating handle 52 includes a slight bend shown as 53,just adjacent the point wherein the operating handle joinsdriving shaft 54. The handle part, shown as 57, is pivotally secured to the end of the operating handle 52 so that one opening the system may grasp the depending portion of 57 and pull outwardly and downwardly with the portion 57 swinging outwardly and upwardly as the handle is rotated The operating handle'52 is made to effect closure through a rotation of 90 with a minimum width dimension. Other operating handle constructions are, of course, contemplated as useful with the invention system.

FIG. 6 shows one side of the driving mechanism which is operated responsive to movement of the handle 52. There would be an identical driving mechanism on the other side of the rear bay receiver frame. In FIG. 6 the front board is shown in the upward position with the bottom portion of the frame shown in phantom at 27. This would be in the position of closure, as indicated in FIG. 5. As indicated in FIGS. 3-5, the front board is carried within the receiver mechanism and then cammed upwardly to effect contact closure. The driving mechanism includes a shaft 54 which is pinned to operating handle 52 by a pin member, shown as 56 in'FIG. 6. Shaft 54 is supported for rotary movement within the lower frame 35, as indicated in FIG. 6. Support is provided by bearings 58 and 60 disposed on each side of cam 66. Each bearing includes an inner race 62 fixed to the shaft, which in turn is fitted within a sleeve such as 64, secured to the outer frame of the rear bay receiver in the manner indicated. Disposed between the bearings 58 and 60 is a cam shown as 66, which includes an eccentric 67, a bearing 68 surrounding and supporting the eccentric and an outer sleeve 69 driven thereby, when shaft 54 and the cam structure is rotated and it drives the board 12 upwardly to effect closure of the contacts. In accordance with a-preferred embodiment, this cam structure is made to be driven overcenter to drive the front board up for an initial closure and wiping engagement between the patchcords and the rear board contact springs and then slightly downwardly to effect a rewipe of the contacts. This kind of mechanism is disclosed in more detail in U.S. Pat. No. 2,927,295 to G. C. Sitz.

The receiver mechanism is shown in'more detail in FIGS. 7-1-0. The receiver mechanism is comprised of four hooks each arranged like the'hook 88, shown in FIGS. 7-10 and each operable in the same or similar manner. It is to be understood that there are righthand and left-hand pairs of books to accommodate the right and lefthand sides of the front board. In FIG. 7 the pin 30 is shown above and out of contact with a hook 88 and just prior to being displaced downwardly to nest within and be supported by the hook 88. FIG. 8 shows the pin 30 nested within the hook 88 and FIG. 9 shows the hook 88 displaced inwardly to carry the front board within the receiver so that the contacts are in the position shown in FIG. 4. FIG. 10 shows the disposition of the receiver mechanism following the camming operation previously described with the contacts in the position shown in FIG. 5.

Each hook includes at its forward end the recess 102 shaped to receive a front board pin such as 30, and the projecting portion 104 which serves to hold the pin within the recess 102 and as a ramp for guiding the pin therein. The hook mechanism is mounted in a recess in the side walls of the rear board frame, such as 34. This recess is shown as 70. A hook frame 72 is secured within recess 70 as by rivets 74. The frame includes horizontal, spaced side walls 76 and 78 and a vertically disposed rear wall 80. Extending across the frame 72 and rigidly attached thereto are roll pins 82, which support the hook 88 from beneath and a pin 84 which supports the hook from above. These pins entrap the hook for sliding movement. The rear of the hook 88 includes an enlarged diameter portion 94 rounded on its inner surface, as at 96 to engage the rearmost pin 82 and the pin 84. There is provided within the hook a slot 90 which receives a compression spring 92 made to engage the rear flange 80 and the hook. This spring tends to push the hook to the right of the frame 72 and of the rear board frame 34. The spring is shown in its relaxed position in FIGS. 7 and 8 and in its compressed position in FIGS. 9 and 10. The upper flange 76 includes, secured thereon, a leaf spring member shown as 86, which is biased down to engage a detent shown as 100 on the top of the book. This leaf spring operates to provide a latching of the hook in the inward position by engagement with detent 100 in the manner shown in FIGS. 9 and 10. The end of the spring 86 and the surface configuration of detent 100 are made so that the spring rides up over the detent as the hook is displaced from the right to the left, or inwardly of the frame. The spring is made sufficiently stiff to hold the hook inwardly against the force of the compression spring 92, which tends to push it outwardly. As the spring clears the detent when the rear board is withdrawn from the receiver mechanism the force of the spring serves to push the hook and therefore the front board to the fully open position, as indicated in FIG. 8. The mechanism disclosed in FIGS. 7-l0 thus operates to receive and position a front board prior to insertion and then to carry the front board in an exact inward movement to effect insertion and then to permit the board to be cammed upwardly and still lock into the board.

FIG. 9 shows the front board inserted, but prior to switch closure and camming action. There is included, aligned with the pin 30, in the bracket 72 a further rounded recess portion 77 which receives the pin 30 as the board is cammed upwardly. A downwardly projecting portion of the flange shown as 75 prevents the front board from being displaced outwardly of the assembly once the camming operation has taken place. The hook and receiver mechanism guides the front board very exactly to avoid damage or premature engagement of portions of the contact spring members of the rear board and the patchcords of the front board.

Turning now to a description of the front and rear boards, reference is made to FIG. 11, which shows the boards spaced apart and prior to insertion of the front board within the rear board receiver. In accordance with the invention, each of the front and rear boards is comprised of a core of plastic material having the outside surface thereof covered over by a metallic covering in the form of a coating. The board cores are typically molded of phenolic resin including a relatively hard insulating and dielectric material. The metallic coating is provided by plating the molded board first with a thin coating of electroless conductive material, such as electroless copper or electroless nickel, which serves to provide a bond between plastic and metallic materials and which can be readily plated upon plastic material. Then an electro-plate metallic material, such as copper, nickel or tin is plated on over the electroless material to provide an outside finish coat and to provide a body for the plating sufficient to withstand the forces of use and sufficient to provide adequate shielding and grounding for the system. In an actual unit constructed in accordance with the invention the core of the board was made of a phenolic resin overplated to a thickness of approximately 0.000025 with electroless copper, which was then electro-plated to a thickness of 0.0005 with electroless nickel. Another embodiment was plated first with electroless nickel and to a thickness of 0.00025 and then plated to a thickness of 0.0005 with tin. A finish or flash coating of silver or other material may be added if desired.

In the construction of the boards the plating is carried across the outer surfaces of the boards and down through the inner surfaces of the apertures in the manner shown in FIG. 11. The front board core 20 is covered by a plating 24 and the front of the front board is then insulated by a thin sheet of insulating material bonded thereto and shown as 25. This sheet is suitably apertured to permit the insertion of patchcords 120. The sheet 25 serves to prevent an accidental grounding of the patchcord during insertion (post-patching) after the system is closed.

The rear board is constructed in the same manner as the front board with respect to a plastic core overplated with metallic conductive material, the core being shown as 40 and the conductive material being shown as 42, in FIG. 11. The apertures 38 each include a projecting flange 39 at one end, as shown in FIG. 13, and are made to receive a plastic insert 130. The inserts include a body l32,'wedge fitted into the aperture and a flange portion shown as 134, made to extend out over the inner surface of the board in the manner shown in FIG. 11. Each insert carries therewithin a contact spring member shown as 110. The contact spring is supported within the insert and within the board by a D-shaped cross-sectional configuration of spring, insert and aperture, best indicated in FIG. 13. The contact spring member includes a support portion 112, which has a D-shape in cross-section fitted into a similar shaped aperture in the insert which has an outer D- shape. This outer D-shape locks the insert to the board to orient the spring therein. Spring orietation is shown in FIG. 6 to include an alternative disposition of the plane of the contact from contact member to contact member. This orientation has been found to more evenly distribute stresses in the rear board assembly which result from deflection of the contact springs by patchcord members.

FIG. 11 shows the construction of the contact spring to further include a terminal portion such as a post 114, which extends out of the rear of the board to receive and be terminated by input and output leads from the equipment served by the system. In accordance with a typical use these leads will be shielded coaxial leads having a center conductor terminated to the body of 114 and a shielding conductor terminated in a suitable fashion to the shielding of the system. The forward portion of each contact member includes a spring 116 which is vertically disposed with respect to the movement of closure of the front board relative to the back board. Spring portion 116 has an extension shown as 118, which is placed at 45 relative to the movement of the spring portion 116. The portion 118 carries thereon a contact bar 119, as shown in FIG. 11. The operation of spring members of this general construction is more completely described in U. S. Pat. No. 2,882,508 to W. S. Watts.

Extending out from the forward face ofthe rear board is a grid comprised of conductive portions 46 and 50 which form a box-like cavity surrounding the rear bay contact members 110. The grid may be made of strips of thin metal sheet material in the manner indicated in FIGS. 11-12 and in FIG. 6. Alternatively, it is contemplated that the grid could be made of a construction wherein the body of the grid is plastic overplated with an electroless and electro-plate metallic material to provide shielding. The grid is secured to and connected to the conductive plating of the rear board in the manner indicated in FIG. 12 through a flange on the outside sheet member shown as 47. The grid flange 47 is held down against the plating of the board through a recess and offset shown as 37, in the rear board frame by means of a clamp member 43 secured to the frame as at 41 FIG. 12 shows a front board inserted within the rear board receiver in the position shown from the side in FIG. 4, which causes the center conductive pin of the patchcord 120 to overlap the contact bar 119 of the rear board contact spring 110. When-the front board is cammed upwardly in the manner previously described the contact pin of the patchcord will engage contact bar 119 to interconnect the patchcord to the contact spring. As can be discerned from FIG. 14, the pin 170 is surrounded by a conductive material formed by a plating shown as 146 which extends out over an end portion 150 of an insulating sleeve 144. When the front board is in position as shown in FIG. 12 the contact path formed between the patchcord and the rear board contact spring is entirely surrounded by conductive material. This includes the grid formed by sheets 46 and 50 and the plating 146, which is made to extend back and contact the shielding of the patchcord. The contact spring 110 is surrounded along its length within the board by the grid and the conductive plating of the rear board.

Turning now to FIG. 14, a patchcord 120 is shown terminated to a shielded lead 122, which includes an outer protective sheath 124., a sheath of dielectric material 126, a braid 125 surrounding 126 and beneath 124. The center of the leadcontains a conductor 128. The lead is stripped and prepared as shown in FIG. 14

to expose various segments of the center conductor, dielectric sheath, braid and outer sheath. An insulating boot 130 is formed over the outside of the metallic portions of the patchcord and made to extend back over the outer sheath of lead 122 to provide support thereto and to protect the connection between the conductive portions of the patchcord and the lead. The main body of the patchcord is formed by a thin metallic shell 134. The diameter of. the shell 134 in its forward portion is controlled so as to always permit 134 to be inserted without undue force within an aperture 18. Toward the center of the shell 134 is an enlarged portion forming an annular flange 136 which serves to limit the insertion of the patchcord within the front board by engage ment with the front surface of the board; namely, the insulating sheet 25, which is shown in FIG. 11. The rear portion 138 of shell 134 is of a reduced diameter and is of a construction to permit it to be crimped inwardly against the exposed braid 125 and against a backup ferrule shown as 140 slipped under the braid and over the dielectric sheath 1-26. This crimping operation may be in any suitable fashion to permanently terminate the braid of the cable to the shell 134 through the portion 138. The shell 134 is staked to a number of further sleeves through indentations as at 142 and 143. These first further sleeves include sleeve 144, which extends within the forward portion of shell 134 and directly supports the patchcord pin member 170. The sleeve 144 is formed of plastic such as nylon, overplated on its outside surface as at 146. The indentation at 143 terminates the shell 134 electrically to the plating on sleeve 144. The interior of sleeve 144 is made to engage the pin 170 at spaced points axially as at 152, to rigidly secure the pin within shell 134. The plating 146 extends only to each end of the sleeve 144 so as not to engage pin 170, which would effectively short out the signal path to the grounding path of the lead. This isolation between the shielding path and the signal path is facilitated in the forward end of the patchcord by a relief shown as 151 beneath 150, which extends back within the body of 144. Toward the forward end of 144 and positioned within 134 is a further sleeve shown as 158. This sleeve is of a plastic material such as nylon and is mechanically secured to shell 134, as by the indentation at 142. The forward portion of sleeve 158 is made to include rounded detents, as at 160, which serve to latch the patchcord within the front board by an engagement with the inner face of the board at the edges of the apertures 18. The outer diameter of the detent portion 160 in its relaxed condition is thus greater than the diameter of the aperture 18. Sleeve 158 is axially slotted to provide a spring action for the detents 160. This slotting is best shown in FIGS. 11 and 12, as 156. The inner diameter of sleeve 158 in its forward end is relieved to permit an inward deflection of the detents as the patchcord is inserted within the patch board. The detents 160 are axially spaced relative to the flange 136 so as to latch the patchcord in an aperture 18 against axial displacement out of the board. This particular mounting and confinement of the sleeve 158 has been found to be advisable due to its being of a resilient material.

The contact pin includes a forward portion shown as 171, which is rounded and preferably plated so as to define a contact surface for engagement with the contact bar 119 of the rear bay contact spring 110. The piniscrimped to the center conductor 128 in a '9 suitable fashion to electrically extend the signal path of the lead forwardly of the patchcord. The rear of the pin is enlarged as at 172 to be received within the sleeve 1 44 and mechanically held therein against axial displacement. To the rear of 172 there is provided a sleeve insert 174 of insulating material which'prevents forced displacement of the pin rearwardly which could cause an electrical short between the signal and the shielding paths. The sleeve 174 is wedged within the bore of the sleeve 144 at one end and made to engage the front end of the ferrule 140 at the other end.

The patchcord 120 has been found to effectively extend the shield of a shielded lead through the front board and at the same time to provide a latching thereof which operates to hold the patchcord in the front board without requiring an excessive insertion or withdrawal force. The latch structure has been found to be capable of repeated use without damage to the plating of the front board. When the patchcord is in use and generally in the position shown in FIG. 12, the force applied to the pin 170 has been found to be quite sufficient to cause the shell 134 to bear against the conductive plating of the front board to effect a completion of contact between the shield of the patchcord and the shield of the board.

In the above description the various boards of the system have been taught as having a shielding structure. It is fully contemplated that the boards may be only partially shielded or that certain boards may be shielded and others may be standard. For example, it is contemplated that half of the apertures in a given board for the front and rear boards may be shielded and the other half of standard construction, or that two of the boards for the front and rear may be shielded, with the other two being standard. The foregoing would permit substantial economies in systems requiring only a few shielded leads.

Having now described the invention in terms intended to enable its preferred mode of practice, we define it through the appended claims:

We claim:

1. A patchcord for use in a plugboard having an insulating core overcovered with a thin metallic material, said patchcord including an inner conductive portion and an outer conductive portion insulated from each other and adapted to be terminated to the inner and outer conductive portions ofa shielded cable and a detent means affixed thereto, said detent means'being comprised of a resilient insulating material and having a geometry to latch said patchcord within-a plugboard and to permit insertion and withdrawal of said patchcord within a plugboard without damage to the said thin metallic covering thereof, and wherein said detent means is held between an outer sleeve of thin conductive material and an inner sleeve of resilient material having a conductive covering bonded to the outer surface thereof.

2. A patchcord for use in a plugboard having an insulating core overcovered with a thin metallic material,

said patchcord including an inner conductive portion and an outerconductive portion insulated from each other and adapted to be terminated to the inner and outer conductive portions of a shielded cable and a detent means affixed thereto, said detent means being comprised of a resilientinsulating material and-having a geometry to latch said patchcord within a plugboard and to permit insertion and withdrawal of said patchcord within a plugboard without damage to the said thin metallic covering thereof, and further including a center conductive pin member and a sleeve of resilient material surrounding and supporting said center pin member along a substantial portion of the length thereof, the said resilient sleeve having an outer covering of conductive material to shield said center pin member, and means to terminate said covering to the shielding of a shielded cable.

3. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof.

4. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof, and said terminating means includes a backup ferrule disposed underneath the shielding of said shielded cable.

5. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof, said detent means comprises a forward portion carrying radially projecting, rounded detent surfaces separated from each other by axially directed slots, and said terminating means includes a rear part of said outer conductive portion which has a reduced outer diameter and a backup ferrule disposed beneath said rear part and beneath the shielding of said shielded cable.

6. A patchcord in removable electrical combination with a plugboard, wherein said plugboard comprises at least one board member having an insulating core overcovered with a thin metallic material, said board member containing a plurality of apertures therein with said thin metallic covering extending over the inner surfaces of said apertures, each of said apertures being adapted to receive a patchcord, said patchcord including a shielded cable having inner and outer conductors, an inner conductive portion and an outer conductive portion insulated from each other and terminated respectively to the inner and outer conductors of the shielded cable, detent means affixed to said patchcord, said detent means being comprised of a resilient plastic material and having a geometry removably latchably engaged within said plugboard and resiliently deformable upon insertion and withdrawal of said patchcord within one of said plugboard apertures without damage to or appreciable wear of said thin metallic covering, and

said outer conductive portion electrically contacting said thin metallic covering and electrically shielding said inner conductive portion, with said inner conductive portion extending through said one of said plugboard apertures.

7. The patchcord of claim 6 wherein said detent means includes a tubular rear portion and a forward portion carrying radially projecting detent surfaces and said patchcord includes an inner conductive sleeve and an outer conductive sleeve dimensioned to receive and support the tubular portion therebetween, with the detent means projecting forwardly therefrom, the said detent means being secured to said sleeves against axial movement relative thereto.

8. A shielded patchcord plug for use with a shielded plugboard having an insulating core with apertures therethrough and overcovered with a thin metallic material, said plug including an'inner conductive member having connector means for electrically connecting it to the innr conductor of a shielded cable and having at its outer end an axially projecting contact pin, a tubular outer conductive member coaxially surrounding said inner conductive member and adapted to fit slidably into one of said apertures and in electrically conductive relation with the thin metallic covering therein, the outer end of said outer conductive member terminating short of the outer end of said contact pin, and the inner end of said outer conductive member being provided with connector means for electrically connecting it to the outer conductor of said shielded cable, and a tubular detent member of resilient, synthetic plastic material positioned coaxially between said inner and outer conductive members, with its outer end extending beyond the outer end of said outer conductive member but terminating short of the outer end of said pin, to leave a portion adjacent the outer end of said pin exposed for conductive engagement with the contact member of a back board, said detent member having near its outer end at least one latch portion which projects radially outwardly beyond the outer surface of said outer conductive member for interengagement with the rear surface of said plugboard, the inner surface of said detent member beneath said latch portion being radially spaced from said inner conductive member to permit said latch portion to be resiliently depressed to fit within said aperture, and inclined cam surfaces at the forward and rearward sides of said latch portions for camming said latch portions inwardly during insertion and withdrawal of said plug into and out of said aperture.

9. A shielded plug as described in claim 8 in which said detent member has a plurality of circumferentially spaced latch portions with longitudinally extending slots therebetween.

10. A patchcord plug as described in claim 8 in which said inner conductive member is provided at its inner end with an axial opening for receiving the bared end of the inner conductor of said shielded cable whereby the inner conductor may be compressed into intimate conductive engagement with said inner conductor, and wherein said outer conductive member is provided at its inner end with an axial opening for receiving the bared end of the outer conductor of said shielded cable around an insulating sleeve, whereby said outer conductive member may be compressed into intimate conductive engagement with said outer conductor with said insulating sleeve insulating said outer conductor from said inner conductor.

11. A patchcord plug as described in claim 10 wherein said insulating sleeve is part of said shielded cable and wherein a tubular supporting ferrule is interposed beteen said outer conductor and said insulating sleeve to support said outer conductor as said outer conductive member is compressed against it.

12. A shielded patchcord plug for use with a shielded plugboard having an insulating core with apertures therethrough and overcovered with a thin metallic material, said plug including an inner conductive member having connector means for electrically connecting it to the inner conductor of a shielded cable and having at its outer end an axially projecting contact pin, a tubular outer conductive member coaxially surrounding said inner conductive member and adapted to fit slidably into one of said apertures and in electrically conductive relation with the thin metallic covering therein, the outer end of said outer conductive member terminating short of the outer end of said contact pin, and the inner end of said outer conductive member being provided with connector means for electrically connecting it to the outer conductor of said shielded cable, and a tubular detent member positioned coaxially between said inner and outer conductive members, with its outer end extending beyond the outer end of said outer conductive member but terminating short of the outer end of said pin, to leave a portion adjacent the outer end of said pin exposed for conductive engagement with the contact member of a back board, said detent member being composed ofa resilient, synthetic plastic material to permit insertion and withdrawal of said plug in said shielded plugboard without damage to the thinmetallic covering thereof, said detent member further having near its outer end at least one latch portion which projects radially outwardly beyond the outer surface of said outer conductive member for interengagement with the rear surface of said plugboard, the inner surface of said detent member beneath said latch portion being radially spaced from said inner conductive member to permit said latch portion to be resiliently depressed to fit within said aperture, and inclined cam surfaces at the forward and rearward sides of said latch portions for camming said latch portions inwardly during inserion and withdrawal of said plug into and out of said aperture. 

1. A patchcord for use in a plugboard having an insulating core overcovered with a thin metallic material, said patchcord including an inner conductive portion and an outer conductive portion insulated from each other and adapted to be terminated to the inner and outer conductive portions of a shielded cable and a detent means affixed thereto, said detent means being comprised of a resilient insulating material and having a geometry to latch said patchcord within a plugboard and to permit insertion and withdrawal of said patchcord within a plugboard without damage to the said thin metallic covering thereof, and wherein said detent means is held between an outer sleeve of thin conductive material and an inner sleeVe of resilient material having a conductive covering bonded to the outer surface thereof.
 2. A patchcord for use in a plugboard having an insulating core overcovered with a thin metallic material, said patchcord including an inner conductive portion and an outer conductive portion insulated from each other and adapted to be terminated to the inner and outer conductive portions of a shielded cable and a detent means affixed thereto, said detent means being comprised of a resilient insulating material and having a geometry to latch said patchcord within a plugboard and to permit insertion and withdrawal of said patchcord within a plugboard without damage to the said thin metallic covering thereof, and further including a center conductive pin member and a sleeve of resilient material surrounding and supporting said center pin member along a substantial portion of the length thereof, the said resilient sleeve having an outer covering of conductive material to shield said center pin member, and means to terminate said covering to the shielding of a shielded cable.
 3. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof.
 4. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof, and said terminating means includes a backup ferrule disposed underneath the shielding of said shielded cable.
 5. The patchcord of claim 2 wherein said outer conductive portion of the patchcord includes flange means for limiting patchcord insertion within a plugboard by engagement with one surface thereof, said detent means comprises a forward portion carrying radially projecting, rounded detent surfaces separated from each other by axially directed slots, and said terminating means includes a rear part of said outer conductive portion which has a reduced outer diameter and a backup ferrule disposed beneath said rear part and beneath the shielding of said shielded cable.
 6. A patchcord in removable electrical combination with a plugboard, wherein said plugboard comprises at least one board member having an insulating core overcovered with a thin metallic material, said board member containing a plurality of apertures therein with said thin metallic covering extending over the inner surfaces of said apertures, each of said apertures being adapted to receive a patchcord, said patchcord including a shielded cable having inner and outer conductors, an inner conductive portion and an outer conductive portion insulated from each other and terminated respectively to the inner and outer conductors of the shielded cable, detent means affixed to said patchcord, said detent means being comprised of a resilient plastic material and having a geometry removably latchably engaged within said plugboard and resiliently deformable upon insertion and withdrawal of said patchcord within one of said plugboard apertures without damage to or appreciable wear of said thin metallic covering, and said outer conductive portion electrically contacting said thin metallic covering and electrically shielding said inner conductive portion, with said inner conductive portion extending through said one of said plugboard apertures.
 7. The patchcord of claim 6 wherein said detent means includes a tubular rear portion and a forward portion carrying radially projecting detent surfaces and said patchcord includes an inner conductive sleeve and an outer conductive sleeve dimensioned to receive and support the tubular portion therebetween, with the detent means projecting forwardly therefrom, the said detent means being secured to said sleeves against axial movement relative thereto.
 8. A shielded patchcord plug for use with a shielded plugboard having an insulating core with apertures therethrough and overcovered with a thin metallic material, said plug including an inner conductive member having connector means for electrically connecting it to the innr conductor of a shielded cable and having at its outer end an axially projecting contact pin, a tubular outer conductive member coaxially surrounding said inner conductive member and adapted to fit slidably into one of said apertures and in electrically conductive relation with the thin metallic covering therein, the outer end of said outer conductive member terminating short of the outer end of said contact pin, and the inner end of said outer conductive member being provided with connector means for electrically connecting it to the outer conductor of said shielded cable, and a tubular detent member of resilient, synthetic plastic material positioned coaxially between said inner and outer conductive members, with its outer end extending beyond the outer end of said outer conductive member but terminating short of the outer end of said pin, to leave a portion adjacent the outer end of said pin exposed for conductive engagement with the contact member of a back board, said detent member having near its outer end at least one latch portion which projects radially outwardly beyond the outer surface of said outer conductive member for interengagement with the rear surface of said plugboard, the inner surface of said detent member beneath said latch portion being radially spaced from said inner conductive member to permit said latch portion to be resiliently depressed to fit within said aperture, and inclined cam surfaces at the forward and rearward sides of said latch portions for camming said latch portions inwardly during insertion and withdrawal of said plug into and out of said aperture.
 9. A shielded plug as described in claim 8 in which said detent member has a plurality of circumferentially spaced latch portions with longitudinally extending slots therebetween.
 10. A patchcord plug as described in claim 8 in which said inner conductive member is provided at its inner end with an axial opening for receiving the bared end of the inner conductor of said shielded cable whereby the inner conductor may be compressed into intimate conductive engagement with said inner conductor, and wherein said outer conductive member is provided at its inner end with an axial opening for receiving the bared end of the outer conductor of said shielded cable around an insulating sleeve, whereby said outer conductive member may be compressed into intimate conductive engagement with said outer conductor with said insulating sleeve insulating said outer conductor from said inner conductor.
 11. A patchcord plug as described in claim 10 wherein said insulating sleeve is part of said shielded cable and wherein a tubular supporting ferrule is interposed beteen said outer conductor and said insulating sleeve to support said outer conductor as said outer conductive member is compressed against it.
 12. A shielded patchcord plug for use with a shielded plugboard having an insulating core with apertures therethrough and overcovered with a thin metallic material, said plug including an inner conductive member having connector means for electrically connecting it to the inner conductor of a shielded cable and having at its outer end an axially projecting contact pin, a tubular outer conductive member coaxially surrounding said inner conductive member and adapted to fit slidably into one of said apertures and in electrically conductive relation with the thin metallic covering therein, the outer end of said outer conductive member terminating short of the outer end of said contact pin, and the inner end of said outer conductive member being provided with connector means for electrically connecting it to the outer conductor of said shielded cable, and a tubular detent member positioned coaxially between said inner and outer conductive members, with its outer end extending beyond the outer end of said outer conductive member but terminating short of the outer end of said pin, to leave a portion aDjacent the outer end of said pin exposed for conductive engagement with the contact member of a back board, said detent member being composed of a resilient, synthetic plastic material to permit insertion and withdrawal of said plug in said shielded plugboard without damage to the thin metallic covering thereof, said detent member further having near its outer end at least one latch portion which projects radially outwardly beyond the outer surface of said outer conductive member for interengagement with the rear surface of said plugboard, the inner surface of said detent member beneath said latch portion being radially spaced from said inner conductive member to permit said latch portion to be resiliently depressed to fit within said aperture, and inclined cam surfaces at the forward and rearward sides of said latch portions for camming said latch portions inwardly during inserion and withdrawal of said plug into and out of said aperture. 